LANDSCAPE ECOLOGY: THE NEED FOR A DISCIPLINE?
Michael R. Moss
Faculty of Environmental Sciences University of Guelph Guelph, Ontario N1G 2W1 , Canada
Landscape ecology has gained international recognition over the past two decades as a field capable of providing solutions to a range of landscape problems. Yet, despite this recognition an examination of the foundation and current framework for landscape ecology shows some inherent weaknesses. These arise, ironically, from the two strong founding traditions of landscape ecology and from its attractiveness to practitioners in many fields with a landscape/spatial dimension. However, it is argued that effective progress cannot be made to solving landscape scale issues without a well defined focus and a theoretical and methodological base to which interdisciplinary adherents subscribe. And without such a central conceptual basis the essential role of training and educating a future generation of landscape ecologists in institutes of higher education will never be fully realized.
The thesis taken in this paper is that landscape ecology has now come of age, but that its healthy, youthful development will be cut off before it matures if it does not recognize and develop its own distinctive core and focus. Furthermore, the diverse issues, that now dominate discussions in landscape ecology, will become marginalized if certain fundamental concepts about landscapes do not emerge to form a clear focus to which such diverse issues can contribute. It will be argued also that unless landscape ecologists agree upon such a conceptual focus for their field, the fundamental questions about landscapes cannot be asked, and hence no particular body of general theory about landscape ecology will emerge. In other words the science of landscape ecology will not develop.
What are some current issues for the field of landscape ecology?
Quite evidently landscape ecology has developed but has reached a critical threshold.
It is increasingly recognized as a field of research, and some of the results of this are being put into practice by landscape architects and resource planners; it has established international journals and basic texts; it has growing cohort of adherents, and it is making a foothold in academic institutions throughout the world. What then is the problem?
Perhaps to start this discussion it would be wise to state what landscape ecology is not. It is not the only field which deals with the landscape and it certainly is not the all-embracing environmental science. It is, however, a field with the potential to make a unique contribution to solving a particular subset of natural resource-based issues.
But to achieve this goal requires answers to three points. First, what fundamental, generic questions does landscape ecology ask about the landscape which are different from those of other fields? Second, what types of information can landscape ecology generate by addressing these fundamental questions? Third, do all adherents to the label ‘landscape ecologist’ subscribe to the same basic focus? My own response to the last question would be „no”. And therein lies something of an answer to the first two questions. Beyond a certain superficial level most people would recognize the continuing existence of two founding solitudes in landscape ecology. These are perhaps best illustrated by reference to Figure 1, where (a) reflects the bioecological perspective and (b) the geoecological perspective. Figure 1(a) largely reflects the context for advances in the discipline in the last 25+ years, particularly from within the United States. Figure 1(b) reflects thinking from the longer established tradition dating back to the mid-part of this century in Europe, based on earlier geographic traditions, and subsequently advanced in state research institutes and academia in the former Soviet bloc. The bioecological approach is derived from, and based almost entirely within the biological sciences, particularly ecology, and reflects the recognition of the need to understand the spatial dimension of plant and animal population and community- scale issues. The geoecological approach is founded in geography, which in its early developmental phase sought to define land systems and regional spatial entities on the basis of the systematic interpretation of land-related components such as landforms, soils, vegetation, human land use impact, and more recently the energy, moisture and biogeochemical forces which integrate these elements to produce distinct landscape units.
Landscape ecology, in its modern guise, has developed under the auspices of its international organization, IALE, which was established as the organization to pull the two dominant themes together in order to take full advantage of the potential synergies between the two approaches (Ruńicka, 1999). Up to now, the two approaches have existed comfortably side-by-side. But has much benefit been derived from this situation? My own reading on this is that IALE and landscape ecologists generally have not capitalized on the potential. As a consequence, should the two themes continue to exist independently, they will inevitably become increasingly divergent, hence obfuscating the real potential of the field. What is needed is an identification of the unifying goals and critical fundamental questions that will form the one focus for (a) the bioecological theme of ecology in the landscape, and (b) the geoecological theme of land(scape) system science. The current underlying weakness of (a) for this scenario is that its main justification is the importance of the spatial perspective to plant and animal community dynamics. This inevitably means that the main reason for its existence is to improve our knowledge of plant and animal communities. The landscape merely is a broader context in which this takes place. To justify the existence of landscape ecology merely as a spatial science is severely restrictive. A spatial dimension is critical to any discipline—geography, ecology, soil science, geomorphology, or landscape ecology—
which deals with variations in character over areas of the Earth surface. But this cannot be its sole justification.
The underlying weakness of (b), the geoecological theme, has been in making assumptions about the superimposition of component data on individual land unit components on the assumption that this generates functional landscape units. In fact, to understand function requires a knowledge of processes, and the study of processes of complete land unit systems which incorporate, not merely combine, a range of pedological, hydrological, geomorphic, lithospheric and atmospheric processes as they interact within these land systems. The diagram (Figure 1(b)) of Leser and Rodd (1991) reflects the limitations of the geoecological approach. The emergence of pertinent process information about land systems remains severely limited, being based on many disciplines whose objects of study are merely parts of a land system and not the systems themselves. Another serious limitation of this sub-field to date is a lack of knowledge of the changing spatial interrelationships of land system data, particularly as these respond to a range of management and land use impacts over time. But what is really needed is a clearly defined, unique approach to landscape system analysis which can generate a set of analytical tools for landscape studies. Ecosystem analysis is not land system analysis at a finer scale. The former is biotically-focused; the latter is both biotically and abiotically focused and integrative. And although there is a spatial dimension within each of these approaches the significance of human impacts and land use change, both temporally and spatially, upon both of these systems is still not well understood.
Fig. 1. Illustrations of the two ‘solitudes’ existing in landscape ecology. 1(a) from Hobbs (1997) shows the bioecological perspective with a focus on the biotic elements and their position in a landscape setting. 1(b) from Leser and Rodd (1991) shows the geoecological perspective based on land units, both a biotic and an abiotic component and heterogeneous land uses (A and B in particular this diagram represent spheres of interest of separate disciplines)(from Moss, 1999a).
Perhaps some degree of reconciliation of the two solitudes has been brought about by the use made by landscape ecologists of remotely-sensed information and geographic information systems. But again these technologies, that are not the preserve of any one discipline, merely provide and display information as one source for problem-solving and for generating further research questions.
Consequently, landscape ecology must reconcile this divide between the two sub-fields or solitudes before they become too divergent and driven by forces from outside the landscape focus. To achieve this goal therefore requires some very fundamental questions about landscapes to be asked, so that the two solitudes both turn to focus inwards on one goal – the understanding of landscapes.
The „disciplinarity” of landscape ecology
It is the problem of disciplinarity which increasingly raises issues concerning the value and potential of landscape ecology. Is landscape ecology a multidisciplinary, a pluri-disciplinary, an interdisciplinary, or a transdisciplinary field? Or is it a discipline of its own, or is it becoming one? These descriptive expressions of disciplinarity are frequently used in various, and often contradictory, ways. However di Castri and Hadley (1986) have summarized the meaning of each of these terms for land use planning and related ecological work. This outline has provided much of the basis for the use of these terms in landscape ecology texts (for example, Naveh and Lieberman 1994). It specifies levels of coordination and interaction amongst disciplines, from the basic to the applied. This relationship extends from single disciplines, as sources of basic research, though multidisciplinarity (where several disciplines are involved but with no interaction), pluridisciplinarity (where there is unco-ordinated interaction between disciplines) to unidirectional interdisciplinarity (where interaction and coordination is imposed by a single discipline), and to goal-oriented interdisciplinarity (interaction and coordination determined by the nature of an identified problem).
Finally, transdisciplinarity exists where interaction involves not only the scientific and technological disciplines in stated goals, but also where planners and administrators become involved in the processes.
Figure 2 places the above discussion of „disciplinarities” into an issue identi- fication and a problem-solving context, and also into an educational and administrative context. Societies, the world over, notwithstanding their political ideologies, generally organize their administrative structures around a set of common themes ranging from agriculture, to environment, resource development and management, health, finance, etc., etc. (line 1, Figure 2). State ministries are invariably the administrative organizers of these themes and they undertake research under these headings either by their own research staffs, state research academies, or councils. Other non-government organi- zations can also be placed within the same thematic groupings, although their goals are invariably more focused within any one of these major governmental themes.
The next question to raise is how well do our traditional academic education and training systems support the means of providing solutions to such problem themes?
Line 4 in Figure 2 illustrates a fairly typical array of academic disciplines found in
universities, world-wide. Can these disciplines, either singly or in combination (i.e. as multi-, pluri-, and unidirectional interdisciplinarity), enable us to address societal issues of the type being discussed here? Experience indicates that virtually all environmental issues are those transcend single discipline bounds. Quite clearly there is only a very weak link between the disciplines and traditional academic training on the one hand, and a majority of identified issues and problems on the other. In other words, our problem-solving abilities to address many societal issues are weak except where these can be clearly and directly linked to the academic disciplines. But such focused issues are rare at the landscape scale and indeed, any definition of landscape ecology almost precludes either problem identification or its solution within these existing narrow academic bounds. Consequently, as administrative organizers work more closely with academics and discipline specialists, new problem-solving vehicles must emerge. As one example of this, the field of landscape ecology has developed both from within several existing disciplines (for example, from within geography and ecology) and from existing transdisciplinary fields or practices (for example natural resource management and landscape architecture). This is shown in Figure 2, line 3.
Often emerging fields like landscape ecology are justified by their proponents as gaining their strength from their interdisciplinary nature. Landscape ecology probably remains perceived by a majority of its adherents as an example of this. This certainly has been its strength as it gained recognition, from the 1940’s in parts of the world, and in its more recent growth phase since c 1980. In other fields of endeavour, however, such a relatively slow rate of progress is atypical. In the field of medicine, for example, there have been major shifts in the nature, structure and content of medical education and its specialisms in the past two decades. New medical disciplines are constantly emerging as older ones disappear. In the environmental field, however, the pace of such developments has tended to be slow as the traditional disciplines, such as geography or ecology, expand their role to address issues and create unidirectional interdisciplinarity; that is, where interaction and coordination are imposed by a single discipline. This results in diverging, rather than converging, perspectives toward solving environmental issues. It may be argued that this has been particularly apparent in our dealing with environmental issues at the landscape scale. Hence, the current state of landscape ecology, in showing tendencies for several distinct unidirectional interdisciplinarities to emerge, will never be able to fulfil its stated objectives since its core, the land(scape), is rarely the primary focus of these disciplines. This focus is rarely acknowledged and consequently the unidirectional interdisciplinarities focus more upon themselves and their connections to their discipline origins than they do to the core problem. This particular perspective forms one of the current dominant constructs of modern landscape ecology; that is that landscape ecology is a spatially oriented, sub-component of the discipline of ecology with a firm foundation in ecosystem theory. The other dominant construct, currently held, is that of landscape ecology as an overarching interdisciplinarity which comes together at times, in various combinations, to solve particular problems; that is, either as goal-oriented inter- disciplinarity or as transdisciplinarity.
It is, however, suggested here that both these constructs pose severe limitations
Fig. 2. A schematic diagram to show the relationships between disciplines, inter-disciplinary structures, public organizations and the theme of ‘Transformation of Agricultural Landscapes’ (from Moss, 1999a).
to developing the problem-solving abilities of a field seeking to provide solutions to a set of problems at a landscape scale. The limitations of the first construct are the dominance imposed by the one discipline based upon the theory and technique developed within that discipline. This discipline base is furthermore only relevant for a particular component (e.g. the plant and animal communities) of a system (the landscape) which is funda-mentally more extensive and inclusive than the biotic component at the surface of the Earth. The fundamental units of the landscape are land systems; that is spatially-bounded entities, with both biotic and abiotic components and with a vertical dimension, extending from the upper lithosphere to the lower atmosphere.
The limitations of the second construct are that, whereas the immediate research problem may be solved, the abilities of a particular interdisciplinary team will be lost, its reason for existing will disappear, and its ability to transfer its knowledge to other, unrelated problems, will be severely limited. Consequently a body of knowledge, and the development of a required theoretical base, does not develop. Unfortunately, both these constructs can be seen increasingly to be the means by which landscape ecology is evolving. They are severely limiting to the enhancement of landscape science.
To summarize this first part of the argument, the weakest point in the information continuum between societal needs (Figure 2, line 1) and traditional academic structures (Figure 2, line 4), is at the problem-solving level (Figure 2, line 3). Here there will be constant shifts between issues and disciplines and opportunities for new fields to develop in order to address emerging societal problems. Landscape scale issues are being increasingly identified, and the means of solving these problems require and justify novel approaches. Hence landscape ecology has emerged and been identified as one problem-solving theme. But it is argued here, that unless it begins to develop the characteristics of a discipline of its own, it will neither develop nor become recognized for its problem-solving abilities.
Landscape ecology: the state of the art
A recent review and statement by Hobbs (1997) very succinctly portrays where landscape ecology is now. He too argues that so far landscape ecology has failed to integrate material from the various disciplines it seeks to bring together. Landscape scale is explained (Hobbs, 1997; Figure 1) and understood to be a study of pattern, processes and change at the scale of hectares to km2. Likewise the critical foci for study of landscapes neatly fall under three interrelated headings—structure, function and change. But as Hobbs points out, despite a few excellent illustrations, landscape ecology has tended to become dominated by the study of pattern rather than of the processes responsible for generating the structures, driving the functions, or bringing about change in the landscape. Consequently, the problems identified, and the future directions suggested by Hobbs would appear to overcome the types of problems identified for the application of landscape ecological principles. But is this viewpoint entirely satisfactory - particularly when examined in the context of the preceding discussion of the dimensions of landscapes - particularly their vertical dimensions? It may be argued that Hobbs’ perspective is that of a unidirectional interdisciplinarian;
that is, the focus comes almost entirely from a biological ecosystem perspective.
This perspective certainly underlies the ongoing dilemma for landscape scientists in that many see landscape ecology as a component of traditional ecological science, but one with a spatial perspective. This perspective is grounded in ecosystem theory and most certainly has led to a good deal of the valued reputation landscape ecology has earned in its relatively short life span. The same argument stands in ecosystem analysis.
Ecosystems have a biotic focus whereas landscapes have a wider biotic and abiotic, or truly biophysical focus.
Such parallel foci on the study of landscapes require also that they be understood from a spatial perspective. Thus, landscape ecology, almost by any definition must address issues of landscape heterogeneity. Yet much of the ecology- based landscape analysis, while recognizing this heterogeneity, in fact analyses only particular homogenous elements, or fragments (woodlots, hedgerows, riparian strips, avian and insect populations, etc.) within these heterogenous landscapes. For land- scape ecology to become more than mere spatial community-scale ecology it must add the abiotic landscape elements to these biotic considerations and evaluate these as the fundamental landscape units—their functional properties, their spatial interrela- tionships across heterogenous landscapes, and how these together provide an additional basis for solutions to landscape problems. These units are the critical elements with which cultural and socio-economic factors interact. A distinctive and unique subject focus can then emerge for the field of landscape ecology. It is upon such a base that the field will be seen to have increasingly wider applications to landscape problems. And as experience is gained in our abilities to address landscape-scale resource management issues, landscape ecologists will no longer be hindered by a lack of a conceptual focus and of the means of understanding that focus.
In contrast to the perspective on landscape ecology that emerges from an ecosystem/biotic focus, Figure 3 outlines a perspective on landscape science/ecology that perhaps typifies the broader, older-established European perspective. Whilst still seen as a „system” the factors considered are much more diverse and there are many processes and connections identified which link this system together. However, the dimensions of this concept, despite the inter-connections linking the system and focusing upon the `land’, have the inevitable result of concentrating upon the influences of various factors upon the `land’ rather than the properties of the land itself.
What does not emerge from this approach is a clear understanding, or recognition, of the particular elements from within each of the peripheral components (the landforms, flora, fauna, etc.) which must be considered to have critical, functioning relationships with the land(scape) core.
In summary, therefore, the two dominant paradigms in landscape ecology at the present time appear to be firstly, that illustrated by an approach primarily from a spatial perspective of ecosystem science with a very strong biotic content, and secondly, from the broader, multi-component approach shown in Figure 3. Both are found to have limitations since the former does not consider land(scape) systems as the basic building blocks of heterogenous landscapes, and the latter considers primarily formative factors upon landscapes. In neither case does the landscape feature as the critical or central conceptual element.
Landscape ecology – the discipline
The next question must then be; to what extent do, or can, these contributory sub- themes add to our understanding landscape? If a landscape is an entity in its own right, with its own properties, how then does the knowledge gained by these sub- themes become incorporated into an improved understanding of the landscape in question? Or, in other words, if, for example, the transformation of the landscape itself is the problem focus, then how can contributions from these sub-themes enhance our knowledge of the transformation of that landscape? Figure 4 outlines a broad approach taken in landscape ecology to addressing the issue of agricultural land transformation in Denmark (see special issue, Landscape Ecology, 1999). Figure 4(A) illustrates a goal-oriented interdisciplinary approach to the problem (see Moss, 1999a, for a wider discussion of this problem). Alternatively, the question may be reversed and asked from the perspective of the land(scape) itself. Then the question to be asked is which
FLORA
VEGETATION CLIMATE
macro & micro
WATER
LANDFORM SOIL FAUNA
ROCK LAND(SCAPE)
HUMANS
Fig. 3. Landscape as an integrated system. Simplified from I.S. Zonneveld, 1988 (Fig.1.2).
indicators of landscape transformation need to be addressed and how can relevant information on impact be gained from related fields or sub-themes, in this case? To put it simply, are we asking about the transformers or the transformed? In asking both of these sets of questions an understanding of the landscape, or land system, and its properties is required; that is, questions are raised about the landscape itself rather than about impacts from peripheral, yet still related, factors. This situation is illustrated in Figure 4(B).
Figure 4(C) illustrates the attributes of landscape ecology as a discipline, in its own right, when based upon the arguments presented here. But has it reached the point yet where it can be fully recognized as such, by its own practitioners and, equally important, by the scientific community at large? Many environmental management problems clearly show that landscape ecology is perceived to have a problem-solving role, and in its short life it has become recognized as a field with a unique contribution to make to a set of environment and resource management issues. Its focus on the landscape, in particular upon the spatial and heterogenous character of landscape, and its investigation of structure, function and change of landscape reflects both societal demands for this knowledge and also the abilities of people to provide this knowledge.
However, a distinctive focus must form about the land, as a landscape system. It is about this focus that questions must continually be raised. To date researchers and disciplines have made contributions to this focus (see Figure 2 ‘existing situation’).
This approach, however, cannot improve our knowledge about the landscape, if these inputs are not a response to questions raised about the landscape itself. And until there are questions about our understanding of landscapes constantly being raised, the theory and the methods required to form a fundamental understanding and a knowledge base will not emerge. Hobbs (1997) notes an increase in the methodological contributions being made to landscape ecology through articles in, for example, Landscape Ecology.
The theoretical debate, however, clearly lags somewhat behind. But, as critical landscape questions emerge, the need to address the theoretical underpinnings of the field must increase. If satisfactory answers are to be provided in response to landscape- scale, land-based problems, then both a theoretical and practical understanding of the core, that is of the land(scape) system itself, must emerge.
This is, however, merely a starting point. Critical questions about landscapes that the majority of landscape ecologists would find acceptable as guiding principles need to be raised and addressed. In so doing, landscape ecologists themselves will have a better idea of the goals and the context for their work. But of equal importance the non-landscape ecologist will have a much clearer idea of what landscape ecologists do and can do.
In other words, the field needs a focus and a profile. Does anyone question what a botanist focuses upon? When you need to know about plants you ask a botanist. But who do people ask now about landscape issues? What questions do they, and should they, be asking about landscapes? What answers can landscape ecologists give that relate this particular dimension to broader environmental issues? By defining core concepts landscape ecologists will avoid the dilemma of geographers—particularly in North America. What do geographers do? What is the focus of geography? The usual, somewhat glib and unsatisfactory answer is that „geography is what geographers do.”
Without any clear focus or role it is little wonder that across North America universities
Fig. 4. Approaches in landscape ecology in (A) the transforming themes are the focus of attention, whereas in (B) attention is upon the landscape itself. Part (C) illustrates the application of land(scape) system knowledge both to specific issues and to the wider demands of providing a stronger theoretical and methodological landscape base for a range of resource management issues.
are closing many departments and programs in that discipline.
By defining and clarifying a landscape focus and by identifying critical questions about this focus, we need not narrow the field nor hinder others from other fields from making their contribution. Indeed, much of the strength of landscape ecology has been in bringing together people from diverse interests. But have we really articulated the value and the purpose of this diversity in clarifying the goals and the purpose of landscape ecology?
As an organizing body IALE should take the lead in raising and profiling these goals. Once this stage is reached then IALE should take the initiative in encouraging a research agenda to meet these goals. Although, as an organization, IALE cannot undertake the research itself it can assume the responsibility for encouraging research about these goals and/or coordinating research already in place which satisfies these goals. IALE should take a much more pro-active role in making this research available.
At the moment we tend to talk to ourselves and we rely heavily on unsolicited contributions to our journals and publications.
Noss (1997) has itemized what he perceives to be the failure and/or inability of universities (in the U.S. in particular and I would add Canada to that list) to respond to emerging (interdisciplinary) fields such as conservation biology. Many of the points he raises apply equally well to landscape ecology. But I would add that as an interdisciplinary focus coalesces that it needs to be treated more as a discipline than an interdisciplinary area. Elsewhere I have expanded upon this question (Moss, 1999a) but will merely restate here that if the necessary theoretical underpinnings of landscape ecology are to develop then the focus must be on the core element—the landscape—and not upon peripheral components of this core element. Or if the focus is upon one of the peripheral elements in a landscape then the relevance of that study should be addressed by a clearly defined link to the core as well as the problem itself. In this way landscape ecology can be both justified and shown to be relevant as a provider of a much needed theoretical basis for much of the wide field of natural resources management–an important point raised by Risser et al (1984) in their seminal document on landscape ecology (see Figure 2 ‘future recommended situation’).
Concluding Comments
Three major questions were raised at the begining of this paper. A possible solution to the issues arising from these questions is outhined in Figure 5. The critical needs are seen to be:
• define the core of the field - the landscape (1)
• explain the conceptual uniqueness of landscape ecology (2i)
• consider this uniqueness from a set of fundamental, conceptual questions and problem-based issues about landscapes (2i and 2ii)
• identify and enhance this core by elaborating a research agenda (3)
• focus this research agenda through consultation, solicitation, coordination and dissemination (3)
• academic institutions, without a tradition of landscape ecology, will only begin to support initiatives from an interdisciplinary base once the goals
of that endeavour are clearly articulated (4)
• the field will only advance as a body of knowledge if it works outward from the conceptual base rather than from the isolated peripheral problem-based approach it now employs (i.e. in 5 and 6)
• there must be constant feedback by all participants to ensure the ongoing development the field.
References
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Moss, M.R. (1999a): Interdisciplinarity, landscape ecology and the ‘Transformation of Agricultural Landscapes’. Landscape Ecol. (in press).
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bioecological approach
geoecological approach
conceptual(2i) questions
(2ii) problem-based
issues
(3) coordinate and
disseminate fundamental concepts and research goals
academic(4) research
increasingly(5) diverse research
enhanced problem(6) solving and application (1)
Fig. 5. A proposed strategy for enhancing the science and the practice of landscape ecology by integrating institutional and academic goals developed from an accepted conceptual basis of
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